After their $190 million experiment ended with a loss to the two-time defending champion Heat in five games in the Eastern Conference semifinals, the Nets now enter the offseason with plenty of uncertainty.

Here’s a look at the five biggest questions facing the franchise this summer, as the Nets hope to re-tool and reload to make another run at the top of the Eastern Conference next season:

1. The uncertain futures of Paul Pierce and Kevin Garnett

For different reasons — Pierce is an unrestricted free agent and Garnett could possibly retire after 19 NBA seasons — there are questions about whether both future Hall of Famers could be back in Brooklyn black-and-white next season.

All indications are, however, that both men will be back with the Nets. Both players seemed to enjoy their first season in Brooklyn, while the Nets have the ability to pay Pierce more than any other team and Garnett is set to make $12 million on the final year of his contract.

2. Can the Nets keep Shaun Livingston?

One of the best stories in the entire NBA this season was the emergence of Shaun Livingston as a critical piece for the Nets, completing a remarkable comeback from a devastating knee injury seven years ago to become a starter for the Nets, giving them a second ball-handler next to Deron Williams and their best perimeter defender.

Now an unrestricted free agent, the Nets will have to hope that the mini mid-level exception — a three-year deal worth roughly $10 million — will be enough to hang on to a player that is sure to command a lot of attention when he hits the open market.

3. Can Brook Lopez come back healthy?

For all of the success the Nets had over the second half of the season, putting together one of the best records in the East and recovering from their slow start to make the second round of the playoffs, the lack of Lopez — the league’s best low-post scorer — was exposed when they couldn’t get an easy basket against the Heat in the Eastern Conference Semifinals.

Lopez, of course, missed 65 games this season plus the playoffs after sitting out following a complicated surgery to repair a fractured fifth metatarsal in his right foot — an injury he has suffered multiple times — by re-positioning the bones in his foot to better distribute the weight throughout it. The Nets will be hoping the surgery has the same level of success a similar procedure did for former Cavaliers center Zydrunas Ilgauskas, who went on to play 11 highly productive years after he had it done.

4. Can Deron Williams rediscover himself?

During his final meeting with the media before heading home for the summer following the Nets’ five-game loss to the Heat, Williams summed up his feelings about his performance over the last two seasons with the Nets, both of which have been plagued by ankle troubles.

“I feel like I’ve kind of let people down, so I don’t like feeling like that,” Williams said. “I take my job serious, I work hard in the offseason, I work hard every day. It’s just real frustrating not to be able to play how I’m capable of playing.”

Williams was set to have an MRI on both ankles last week, and said he was to meet with the Nets’ foot and ankle specialist, Dr. Martin O’Malley, on Monday, and didn’t rule out the possibility of some kind of surgical procedure on his ankles. But regardless of whether he has surgery or not, the Nets need Williams to return to the form he displayed in Utah, when he was arguably the NBA’s best point guard and the Nets were lauded for trading for him.

5. Can they infuse the roster with young talent?

With no picks in a loaded draft, the Nets will likely purchase a second round pick, at minimum. But will they try to make a trade to get into the first round and try to add another young player to Mason Plumlee, their promising first round pick in 2013? That remains to be seen.

There’s also the status of Bojan Bogdanovic, the Nets’ second-round pick in 2011 who is set to be a free agent after spending the last three years with Turkish power Fenerbache Ulker. After Bogdanovic nearly joined the Nets last year, if the Nets fail to sign Livingston he could be an option for them to bring over with their mini mid-level exception.